A nephew of Mana Party leader Hone Harawira has lost an appeal against a jail sentence handed down after he chased and beat a 12-year-old boy.

Mau Harawira was sentenced, in July last year, to three years and two months' jail for a drunken home invasion in which he chased the boy into his house and beat him in his bedroom.

Harawira appealed the sentence on the grounds that it was manifestly excessive.

His lawyer said the judge's starting point was too high and Harawira had not been given enough credit for a guilty plea and for his show of remorse.

The Court of Appeal, in a judgment released today, said it accepted the sentence was "stern"

"But we are satisfied it was within range. We are not satisfied that the judge erred."

At sentencing on August 24, 2012, Judge David Harvey said Harawira had been drinking at a Blockhouse Bay, Auckland, address before going to a nearby beach, where the 12-year-old complainant was playing with a toy.

"For some reason or another you decided he was making disparaging remarks about you," the judge said.

"You decided to wreak your vengeance on him, a boy."

The victim was chased from the beach into his home.

Harawira entered the property through the front deck and found the boy in his bedroom. He slapped him and threw him to the ground.

He punched and kicked the boy's head and torso as he lay on the ground, curled in the foetal position, trying to cover his head with his hands, the judge said.

The boy was dragged outside by his hair and slapped on the head several more times.